Price as reviewed:
£100
Hope RX4 road disc caliper is a brake upgrade for road and gravel bikes that use hydraulic disc brakes from Shimano, SRAM or Campagnolo.
Disc brakes have become popular on road and gravel bikes because they offer better braking in all conditions. But not all disc brakes are equal. Some have problems with power, consistency, noise or rubbing.
Hope has been making disc brakes in the UK for over 25 years and has a lot of experience in this field. The RX4 is its first road and gravel specific disc caliper and it promises to improve the braking performance of any bike.
The RX4 has a four piston design, instead of the usual two pistons that most stock road brake calipers have. This means more contact area with the pads, more power, more modulation and less rubbing. The caliper is also made from a single piece of aluminium, which makes it stiffer and lighter than most stock calipers.
The RX4 works with your existing shifters (if you already have hydraulic brakes) and comes in different versions for Shimano/Campagnolo or SRAM systems. You can also choose between post mount or flat mount standards to fit your frame and fork. And you can pick from various colours to match your bike.
The RX4 does not come with rotors, so you will need to buy them separately or use your existing ones. Hope recommends its own rotors, but I have also used Shimano and Tektro rotors without any issues.
You will also need to install the RX4 yourself or get it done by a bike shop. Hope provides clear instructions and all the fittings you need, but you will also need a bleed kit and hydraulic oil for your system. The installation process takes some time and patience, but it is worth it to get the best performance out of the brakes.
The RX4 delivers on its promise. The brakes feel smooth, powerful and responsive. You can easily control your speed with one finger on the lever, even on steep descents or wet roads. The brakes are also quiet and don’t rub on the rotors. They are the best disc brakes I have ever used on a road or gravel bike.
